Apparatus for distilling and cracking crude petroleum and distillate



Aug. 24 1926.

C. M. PAGE APPARATUS FOR DISTILLING AND CRACKING CRUDE PETROLEUM ANDDISTILLATE Filed August 26, 1920 2 Sheets-Sheet 1 Aug. 24 19% 1,597,476I C. M. PAGE APPARATUS FORDISTILILING AND CRACKING CRUDE PETROLEUM ANDDISTILLATE Filed August 26, 1920 2 sheets $heet 2 Caz M'PHGE PatentedAug. 24, 1926.

' UNITED STA-TIES" 1,597,416 PATENT oFFica.

, cum in. Pass, or CHICAGO, rumors, ASSIGNOR .ro snonsn FAJBYAN, orennnva,

- rumors.

arramrus FOR nrs'rnmme AND C ACKING cnnnn rnrnorn'un AND DIS'IILLATE.

Application filed August 26, 1920. Serial No. 406,179.

In the manufacture of gasoline or motor spirits by the treatment of highboiling point, residual, particularly the residual from the fractionaldistillation of paraffine base petroleum, after the lowerboilingdistillates are removed, a lower boiling point' roduct of the parafiineseries "is obtained y cracking. This is accomplished by raising theboiling point of the liquid residue by means of back pressure on theliquid and vapors which are maintained under such pressure throughouttheir course from the still'through the condenser and while undergoingcondensation. This process is I known as theBurton process and suchdistillation of petroleum under pressure has been safely carried out ona large scale.

However, in this process and in any of the many allied-processes thegreat danger and chief difiiculty is due to the deposition of hardflinty coke on the inner walls of theheating element. Some-who have hadconsiderable experience in cracking oil have said that the coke isforced into combina tion with the iron, making it brittle and utterlyunable to withstand the high temperature' and pressure employed At anyrate, the greatest deposition of the carbon occurs where. the wall ofthe still is hottest,

-causing a local overheating at that point.

Under such conditions the strength of the steel becomes an unknownquantity and as likely as not it yields to the stress without anywarning. Oil 'vapors of a temperature around 650 F. ignite spontaneouslywhen they evolve from a still into the surrounding atmosphere and incracking processes the temperature is 750 to 850 F., and' even higher;hence the manifestdanger of cracking petroleum oil under such highpressures. 1

The resent invention relates to a process of' cradkingpetroleum anddistillate in a still such as the still used in the Burton process, butwhich eliminates the production of coke on the walls of the still,thereby ob v-iating all danger due' to the weakening offthe steel at.the points where thecokeusually accumulates;

e Another fact'brou'ght out in the Burton process is thatthe depositionof coke '.011'

vertical heating surfaces is very. much less, being about one-third toone-fifth. of the amount deposited'i'on the upper side of a horizontalsurface, such as an ordinary still bottom, in a given length of time.

An object of my invention therefore is to provide a heating element forthe cracking ofpetroleum-and distillates in which the heating surfacesare practically all vertical,

thereby eliminating the de to an appreciable extent.

Also, in thepetroleum cracking industry,

it has been shown that the'ratio between the volume of oilheated and thearea of the heating surface of the apparatus employed is an importantfactor. This relation may position of coke perhaps be moreclearlyunderstood if it is approximately proportional to .theheated surfaceincontactwith the oil. v

Another important object of my :inven- .tion is the \provision of means,whereby a.

thin film of oil is always maintained in contact with the heatingelement and the heating element itself is constructed so that a maximumamount of heating surface is provided in a minimum amount of volume ofthe heating element. 7

A furtherobject of my invention is the provision of means whereby partof the heat generated for the cracking of the distillate is electricallyproduced, and this is accomplished by means of a high frequency, highvoltage current which produces eddy currents of great amperage whichgenerate the heat in a heating element contained in the stiil'itself. 1

Astill further object of my invention is to provide a method ofutilizing any excess heat which-is generated'by my process in heating anadditional quantity of oil for a succeeding process of fractionaldistillation or cracking in another still.

" Another object of the invention is the use. of a high voltage, highfrequency current of small amperagewhich results in the production ofan: oscillating magnetic field through which the oil passes, and thisproduces a high molecular tension in the oil,

causing the 'molecules of the heavier hydrocarbons to break downor'crack with greater ease and also tends to the practical" eliminationof theproduction of fixed gases.

- this invention will be apparent from the disclosures in thedrawingsand specification.

The invention (in a preferred form) is illustrated in the drawings andhereinafter more fully described.

On the drawings: Figure 1 is 'a side elevation of an ap aratusconstructed in accordance with my 1nvention? v -Figpre 2 is an enlargedside view, partly in section, of a single still head showing myparticular cracking cells installed therein. Figure 3 is asectional viewof a cell taken on the line 3-3 of Figure 2. Figure 4 is a sectionalview of the same cell taken on theline 4-4 of Figure 2.

Figure 5 is another sectional view of the cell taken on the-line 5-5 ofFigure 2 with parts in elevation.

As shown on the drawings: The apparatus consists essentially of a still6 connected by suitable piping 8 to a condenser 10 and a receiver 12 forthe condensed product, all' connected in an air-tight manner and adaptedto be operated under pressure. A gas vent 14 is provided in the.receiver in order'to permit the escape of accumulated gases .if thepressure in the system should rise above a predetermined point. v

The'still 6. is suitably set in a foundation 16, made of brick orconcrete,,or any suitable material, to permit of the still beingheatedby a coal or gas fire in the usual way, a furnace therefor beingprovided at 18 and a fiueat 19. The temperature in the still and vapordelivery pipe is maintained at about the end, boiling oint of gasolinewhich is a variable factor ependent upon the pressure .on the system.Located within the still and adjacent the bottom thereof are what I termthe cracking cells or chambers, which constitute the ch ef elements ofmy invention,.andone or more are installed in each still" according tothe capacity thereof.

These cracking cells consist of an outer double-walled jacket "20 ofmetal having communicating therewith pipes 22 and 24, whlch extend out.of the still proper and permit of circulating a fluid medium throughsaid jacket for pur oses of temperature regulation and also for heatexchange. This jacket is constr cted with an external hood 26, the edgeof which extends below a series of openings 28, communicating betweenthe interior chamber enclosed by the double-walled jacket 20 and theinterior of the still properr This hood is designed to fill with thevapors of the low boil-. ing point products as they are formed withinthe interior of the cracking cells 20 and the vapors prevent the flow ofliquid oil'through the cell by thermo-siphonic action. Oil enters thecell through the holes 30 near the within the cell.

- provided with holes 30 near the base, which permit the easy entranceof oil from the still to replace that which is cracked and escapes as avapor through the upper holesand under the hood. The walls of theseholes 30 may be inclined upwardly and inwardly to .80 prevent thebacking up and escape there'- through of the more highly heated railsWVithin the chamber enclosed by the double-walled jacket 20 is placed acoil of metallic tubing or suitably constructed stranded wire cable 32consisting of 'a number of turns in the form of a helix, one end 34 ofwhich is grounded to the chamber or to the still in a suitable manner toconduct electric current, and the other end of this coil passes throughan insulating bushing 36 of porcelain'or other suitable material locatedin the sides or top of the jacket and thence is electrically connectedby a cable 38 through .95 another insulating bushing 40 in the still orstill head to the external electrical apparatus which forms an importantpart of this invention. Within the helical coil 32 contained in thecracking cell and supported by 1 an insulating base 33 of orcelain orthe like is a bundle of loosely ound rods or metallic wires 42, whoselength runs vertically through said coil or helix. The spaces be tweenthese rods or wires constitute the 'areat in which the cracking effectis induced in the oil body, and byreason of the great heat generated,the large surface area presented, and the thinness of the sheets of oil,I

cracking is effected with great rapidity and of a spark gap 44, acondenser 46 and a volt- 12 age transformer 48 suitably connected to asource of alternating current through a manually operative variablereactance regulator or-pa1r of choke coils 50 and 52, the whole designedand so proportioned as to 1 produce a high frequency oscillatingelectric current through the condenser 46, spark gap 44, connectingleads 54 and 56 and the helix 32 enclosed by the double-walled jacket 20of the cracking cell. 7 13o A blowout pipe for the cell is provided at58, which communicates with the interior of the cracking cell and isadapted to allow the escape of the oil within the crackingv cell atdesired intervals. Any'free carbon liberated'during the cracking processexists as.a .finely divided suspension and is practically confinedwithin the cracking cell. 1 The blowout pipe offers a means of removingthis at intervals without the necessity of checking the operation of thestill,'the free carbon mixed with the oil being ejected as a sludge. Thedistillates to be cracked into gasoline are fed into the still by apipe, and the level of the oil in the still is maintained "'atmcon'stantvalue, this being determined by means of the gauge 62, thepressure bein% determined and regulated by gauge 84 an safety valve 86,while a thermometer is provided at 88.

The operation is as follows: Oil or distillate, preferably the latter,having been introduced into the still by means of the pipe 61, is heatedtherein by externally applied heat in the furnace 18 until a temperatureand pressure approximating that of the end point of gasoline 'at the.given pressure is attained. Then the transformer 48 is brought intooperation and comparativelyQlow voltage currents of great amperage arethereby induced in the bundle of rods or wires 42, these high amperagecurrents beiiig called eddy or Foucault currents. The passage of thecurrent of high frequency through the helix 32 induces these eddy orFoucault currents in the bundle of wires 42/, which are preferably madeof iron or copper, but may be made of any suitable material, and metalsacting as catalyzers,

such as nickel, are especially advantageous;

with some classes of oils. These eddy currents result in the productionof great heat,

art of which heat is due to hysteresis. urther, the high frequencyoscillating 45 magnetic field produced around the helix 32 passesthrough the thin films of oil surrounding the rods or wires of the core42 andresults in the production-of a high molecular tension in the oil.This molecular tension, together with a suitable heattand a properpressure maintained on the system,

causes the molecules of the heavier hydro-.

' V carbons to break down or crack with ease into low-boiling pointhydrocarbons of the saturated class, and the production of fixed gasesis very low.

, formed.- these being vapors at the temperature of the" surroundingoilin j the still proper, escape untler the edge of the'hood,

As thelow boiling'point "products are the core of-rods 42, which ossessaboiling polnt above that of.the desired product, are condensed bycontact with the double-walled jacket through which is circulating asuitable medium at the correct temperature to ,70 absorb this excessheat, and if any vapor escapes under the hood with the vapors of saidproduct it becomes condensedwithin-the oil in the still during itsupward passage through the same. In either event, all of the vaporizedproducts with a boiling point above that of the desired end point for aglven pressure are eventually returned to the cracking cell for furthertreatment.

I propose, in cases where it may be feasible, to pump crude oil throughthe double walled jacket 20, asshownin Figure 1, by means of the pump 60and pipe 22. This 011, after cooling the vapors in the cracking cell,will emerge through the outlet pipe 24 8 and will then be conducted toan ordinary straight run still 66, which still is provided with a pipe68leading to a condenser 70 and a receiver 72, liketvise provided with avent pipe 74:. This crude oil, after being introduced into the still 66,will, with a slight addition of heat, be fractionally distilled and thegasoline and kerosene cuts made. Thus the excess heat-of the crackingcell' transferred to this oil by means of the double-walled jacket canbe made to serve a useful purpose in preparing the crude oil for furthercracking treatment and-in removing its originally contained gasoline andkerosene. Theworking pressure of the systemmay vary in practice from afew pounds gauge to as much as 80 pounds gauge, dependent upon theorigin and-nature of the oils being treated and the characteristics ofthe product desired. The input of electrical energy is convenientlyregulated by the adjustment of the variable reactance regulators 50 and52, and in practice electrical energy may be raised from the zero pointuntil a maximum amount of gasoline is distilling over associated with aminimum amount of fixed gases.

It will ,be seen that herein is provided a new and novel means forcontinuously cracking petroleum and distillates in which the heatapplied to the distillate is electrically generated and highlyconcentrated, thereby eliminating practically all of the troubles due tothe accumulation of carbon in the still, and further taking advantage ofthe high molecular tension due to the passage of the high frequencyelectric current which aids to break up the hydrocarbon molecules. Also,by this apparatus the troubles and danger due to the deposition of'hardflinty coke on the walls of'the still are completely avoided and thefact that coke does not so readily accumulate on a vertical heatingsurface is taken advantage of'in a highly eflicient manner. Anotherbeneficial result is attained in the conservation of fuel by the heatexchange apparatus, in which the crude oil used in one stillas acondensing medium is keptheated and by a further slight addition of heatis then fractionally distilled in a second still. Further economyofheatis effected, because in the operation of an ordinary crackingstill, somuch excess heat must be applied that a great many heat units aredissipated and lost, while in this process only a moderate heat isapplied from the outside of the still, beingthat'necessary to bring thecontents to about 410 F. at atmospheric pressure, and the additionalheat necessary to effect the cracking is developed directly inthecracking cell and is therefore highly concentrated with a minimum ofloss.

I am awarethat many details inthe construction and operation of both thecracking and electrical apparatus may "be varied through a wide range,and'I therefore do not desire to limit the patent, when granted,otherwise than is necessitated by the prior art. y

I claim as my invention:

1. In an apparatus for cracking oil by heat and pressure, a multitude ofclosely situated vertical metallic surfaces and means surrounding themfor electrically heating the same.

2. In an apparatus for cracking oil coniprising a gas-tight,still, acondenser and a receiver, a heating element including abun dle ofmetallic rods within the still surrounded .by a helix adapted to carryhigh frequencyelectric current.

-3. In an apparatus for cracking oil including a still and a furnaceforheating the still eXternally,-an velectrically heated cracking cell inthe still, a hood enclosing the up per portion. of the cell, andmeansfor automatically returning any vaporized products having a boilingpoint above that of the desired product to the cell for furthertreatment. 5

4. In an apparatus for cracking oil comprising a gas-tight still, acondenser and a I receiver; a heating. element including a bundle ofmetallic rods within the still, surrounded by a helix adapted to carryhigh frequency oscillating current, and a generator for such currentincluding .a condenser and a spark gap.

5. In an apparatus for treating oils insubscribed my name.

' CARL M. PAGE.

